Free point indicator



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Nov. 14, 1967 1. H. KIRBY 3,352,360

FREE POINT INDI CATOR Original Filed Oct. 19, 1965 5 Sheets-Sheet 1 4245 X/wa Nov. 14, 1967 1 H KlRBY n 3,352,360

FREE POINT INDICATOR original Filed oct. 19, 1965 3 Sheets-Sheet 2 /fBYOMMKW ATTO/FNV Nov. 14, 1967 1. H. KIRBY Il 3,352,360

FREE POINT INDICATOR ATTORNEY United States Patent O 3,352,360 FREEPOINT INDICATOR John H. Kirby II, 7030 N. Stardust Circle, Rte. 6, Box644, Tucson, Ariz. 85702 Continuation of abandoned application Ser. No.497,694, Oct. 19, 1965, which is a continuation of abandoned applicationSer. No. 424,063, Jan. 7, 1965, which in turn is a continuation ofabandoned application Ser. No. 193,776, May 10, 1962. This applicationDec. 5, 1966, Ser. No. 599,320

3 Claims. (Cl. 16655.1)

This invention pertains generally to well apparatus and particularly toapparatus used in finding the stuck-point of a tubular structure in awell bore and removing as much of such tubular structure as possible.

This application is a continuation of my copending application S.N.497,694 tiled Oct. 19, 1965, now abandoned, which copending applicationis a continuation of my prior application S.N. 424,063 tiled Jan. 7,1965, now abandoned, and which application in turn is a continuation ofmy prior application S.N. 193,776 tiled May l0, 1962, now abandoned, andentitled, Free Point Indicator.

Stuck-point or free-point indicators are known to the oil explorationand production industry and have been used extensively during drillingof wells and during workover operations. Such stuck-point or free-pointindicators generally utilize various combinations of electrical circuitswherein capacitance, inductance, and reluctance or combinations thereofare used to determine the point at which a tubular member Such as casingor tubing is lodged in a well bore. Some of the known stuck-point orfree-point indicators have been partially satisfactory but most of theknown stuck-point or free-point indicators can be utilized only withferrous drill pipe or tubing. Also some of the known stuck-point orfree-point apparatus do not provide means for severing the drill pipe ortubing immediately above the stuck-point to thereby free an optimumamount of the drill pipe or tubing.

Thus, it is an object of the present invention to provide an improvedmethod for determining the stuck-point of tubular structures in a wellbore.

Another object of the present invention is to provide apparatus whichmay be utilized in determining the stuckpoint of a tubular member in awell bore regardless of the material composition of such tubular member.

Yet another object of the present invention is to provide improved meansand methods for determining the stuck-point of a tubular structure in awell bore, such means and methods also providing severance of suchtubular structure during the initial trip into the well bore.

A still further object of the present invention is to provide apparatusfor determining the stuck-point or freepoint of a tubular structure in awell bore, such apparatus being operable from either a wire line or amultiple conductor cable.

In the drawings, FIGURE 1 is a partial-sectional, elevational view of awell bore and apparatus wherein one embodiment of the invention isincorporated;

FIGURES 2A and 2B combined are a sectional, elevational view of oneembodiment of apparatus wherein the invention is incorporated, suchapparatus being in a locked position;

FIGURES 3A and 3B combined are a sectional, elevational view of theapparatus shown in FIGURES 2A and 2B such apparatus being in an unlockedposition;

FIGURE 4 is a front elevational view of a slip segment of the apparatusof the present invention; and

FIGURE 5 is a rear elevational View of the slip segment shown in FIGURE4.

Briefly stated, the invention incorporates a system including wellapparatus which is lowered on a tlexible ICC line inside a tubularmember such as drill pipe or tubing. Such well apparatus is lowered tothe approximate depth where the tubular member is stuck and then thewell apparatus is pulled upwardly by the flexible line, thereby causingmeans of the well apparatus to engage the inside portion of the tubularmember. Suitable registration means are coupled to the flexible line atthe surface of the earth so that when the well apparatus is pulledupwardly by the flexible line, relative movement between the tubularmember and the exible line may be registered as the tubular member andthe wire line are tensioned simultaneously from the surface of theearth. If the stuck point of the tubular member is deeper than thechosen testing point, the registration means will indicate that thetubular member is moving relative to the exible line. The well apparatusthen is lowered deeper into the well bore and the test is repeated atvarious depths until the registration means indicates that no relativemovement is occurring between the tubular member and the flexible line.The registration means includes depth indicating means tor indicatingthe depth at which the well apparatus is located and consequently thedepth at which the test is being made. Subsequently, releasing meanssuch as a go-devil releases the means of the well apparatus fromengagement with the tubular member to allow removal of the wellapparatus from the well bore. When the releasing means, engaging thetubular member, optional means such as an explosive charge couplable tothe well apparatus may be detonated thereby severing the tubular memberso that the upper, free portion may be removed from the well bore.

Referring now to the drawings in detail, FIGURE 1 is apartial-sectional, elevational View showing well apparatus 10 suspendedon a flexible line 12 in a well bore 14 traversed by a tubular structure16. Tubular structure 16 may be drill pipe or tubing compressed of aplurality of longitudinal sections coupled together by suitable meanssuch as drill collars similar to drill collar 18.

The tubular structure 16 is coupled to a derrick 20 having a travelingblock 22 to which is coupled elevator apparatus 24. Such elevatorapparatus is well known in the art and includes elevator bails 26 and 2Scoupled to spider 30. Spider 30 is coupled to tubular structure 16 whichpasses through rotary table 32. Adapted for positioning on the rotarytable 32 is a structure 34 having sheaves 36, 38, and 40 coupled theretofor engaging ilexible line 12. Flexible line 12 is coupled throughregistration means 42 to drum 60 on which the iiexible line is wound.Drum 60 may be mounted on a vehicle trailer 62 having means 64 forrotating drum 60. In the described embodiment of the invention a wireline has been selected but any suitable exible line, including'conductorcable may be eifectively utilized.

Registration means 42 may include means 44 for registering the pay outor amount of line which has been taken oftr of drum 60 therebyindicating the depth of well apparatus 10. Registration means 42 alsoincludes suitable apparatus for registering changes in tension on theline 12. The change in tension on line 12 may be recorded on a suitablestrain gage 46 which is coupled in a suitable manner to sheaves 48, 50,and 52. Although registration means 42 is shown disposed some distanceaway from the derrick, the location of the registration means isdictated primarily by choice of the operator thereof so long as theflexible line will record changes in tension thereon.

A feature of the present invention is that a single operator may bepositioned near drum 60 on the trailer 62 and such operator may visuallyascertain the amount of flexible line which has been taken off of drum60 while also operating means 64 for -applying tension to flexible line12. When tension is applied to the line 12 by reversing the pay-outrotation of spool 60, the operator may visually determine from theregistration means 42 whether or not a change in tension occurs onflexible line 12 as tension is applied to tubular structure 16 throughelevator apparatus 24. Thus through the actuation of elevator .apparatus24 and the tension which is applied to flexible line 12, relativemovement between the tubular member 16 and the flexible line 12 may beregistered.

Well apparatus is lowered through the tubular structure 16, withperiodic tests being made as outlined above to determine relativemovement between tubular structure 16 and flexible line 12. As long asthe tested portion of tubular structure 16 is free, relative movement.will occur and the consequent change in tension on flexible line 12 willbe indicated on strain gage 46. At test points below or at the stuckpipe location, there will be no change in tension on flexible line 12since the portion of the tubular structure 16 immediately above the wellapparatus 10 will not stretch or move. In choosing test points whilepracticing the present invention, it is not necessary to utilize acollar locator as required in many of the prior art freepoint indicatorsalthough a collar locator may be used as means for engaging the tubularstructure 16. As will be explained subsequently, related means such asan explosive charge may be coupled to the lower portion of wellapparatus 10. Well apparatus 10 is adapted for unrestricted downwardmovement in tubular structure 16 but upward movement of wellapparatus 1) occurs` only after a release mechanism in such wellapparatus has been actuated. Well apparatus 10 will now be described indetail.

FIGURES 2A and 2B taken together are a sectional, elevational view ofwell apparatus 10 in locked position. Well apparatus 10 is similar insome respects to structure disclosed in my copending applicationentitled Jet Pipe Cutter Serial Number 117,540 filed June 16, 1961.

Well apparatus 10 comprises an upper section 120 to which middle section158 is coupled. Lower section 168 is coupled to middle section 158.

Upper section 120 includes a shear plug 112 to which flexible line 12 iscoupled. Disposed upwardly from shear plug 112 is a latch release plug114 having a go-devil cushion 116 disposed therein. Intermediate theshear plug 112 and latch release plug 114 is release plug spring 132which causes plug 114 to remain near the uppermost portion of uppersection 120. Pivotally mounted on pin 126 are latch members 122 and 124having fingers 132 and 136 which are normally in engagement with mandrel138 having a head 140. An elastic ring 128 positioned on the outside ofupper section 120 provides a holding force for retaining fingers 134 and136 in engagement with head 140 while the release mechanism is locked. Asimilar elastic ring 115 acts as a retainer when the release mechanismis unlocked as will be explained subsequently. Fishing wickers 118 areprovided on the upper portion of the well apparatus for fishing out ofthe Well bore in a known manner when necessary.

Middle section 158 of well apparatus 10 may be substantially tubular instructure and disposed therein are means such as slips for engagingtubular structure 16 when the well apparatus is moved upwardly. Suchmeans will be described in more detail subsequently.

Mandrel 138 is partially disposed in middle section 158. Aperture 139allows the upper portion of mandrel 138 including head 140 to movedownwardly when the Well apparatus is being released into an unlockedcondition. Mandrel 138 includes a shoulder section 154 and lower mandrelsection 156. The lowermost portion of mandrel 138 is tapered therebyforming a tapered mandrel 160. Resilient means such as a spring 146 ispositioned between shoulder 148 and shoulder section 154 of mandrel 138.

Resilient means such as a light spring 152 is disposed between shouldersection 154 and ring 157.

Means which may include slips 170 and 172 are dismeans such as screws174 and 176. Engaging means such as teeth 173 on slip 170 and teeth 175on slip 172 are used for engaging tubular structure 16 when the wallapparatus 10 is cocked and pulled upwardly with the flexible line 12.Slips 170 and 172 may be changed quite easily to accommodate variousdiameters of tubular structures thereby alleviating the necessity of alarge inventory of complete well apparatus 10. Only the slips of thewell apparatus need to be replaced for different diameter tubing.Downward movement of the well apparatus 10 in tubular structure 16 isunrestrained as is apparent from the configuration of the teeth on slips170 and 172. Although friction means have been described for engagingthe wall of the tubular structure, means such as a collar locator mightbe used with only slight modification to the apparatus shown anddescribed.

Lower section 168 of the well apparatus may be a bull plug threadlycoupled by threads 181 to middle section 158. A pad 182 is positioned onthe upper portion of lower section 16S with suitable means such as screw183. In lieu of pad 182 and screw 183 other means 190 may be coupled tothe lower portion of lower section 168 or substituted for lowersection168 completely. Means 190 may be detonating means, for example,for severing tubular structure 16 after the stuck-point of tubularstructure 16 has been determined.

Referring again to FIGURE l, in practicing the invention, structure 34is positioned over the well bore as shown, with well apparatus in acocked position as shown in FIGURES 2A and 2B, being coupled to fiexibleline 12. In locating the exact stuck point or points of tubularstructure 16, the approximate stuck zone generally will be known. Means44 is set so that as well apparatus 10 is lowered in the tubularstructure 16, the depth of the well apparatus 10 will be shown on means44. When the uppermost part of the stuck pipe zone has been reached bythe well apparatus 10, the rotation of reel 60 is reversed so thatpredetermined tension of the order of 100 pounds is applied to flexibleline 12 as the friction means engage the tubular structure 16. Theregistration on strain gage 46 is noted and then the string of piperepresented by tubular structure 16 is pulled upwardly. As long as thestring of pipe above the well apparatus is free, there will be movementof the needle in strain gage 46 since the well apparatus 10 will belifted somewhat as the entire upper part of the string of pipe is liftedand the tension on the flexible line is thereby decreased. The wellapparatus 10 is gradually lowered deeper, the friction means allowingfree downward movement but restraining upward movement of the wellapparatus 10 when the same is in a cocked position. When no movement ofthe strain gage needle occurs the stuck pipe zone has been located.

The well apparatus 10 must be uncocked or released t0 allow removalthereof from the tubular structure 16 and suitable releasing means areutilized to cause the slips to move radially inwardly as shown inFIGURES 3A and 3B. Such releasing means may be electrical, pneumatic,hydraulic, or of any type designed to cause the friction means to bereleased.

The releasing means in the described embodiment of the invention is ago-devil 200 which is dripped along w1re line 12 to engage latch releaseplug 114 at cushion 116. Latch release plug 114 moves downwardly therebypivotally moving fingers 134 and 136 out of engagement with head ofmandrel 138. Spring 146 provides sudden downward movement of the mandrel138 so that the tapered mandrel is forced against pad 182. Such downwardmovement of mandrel 138 and tapered mandrel 160 causes radial inwardmovement of slips 170 and 172 thereby disengaging teeth 173 and 175 fromthe tubular member 16. Thus the well apparatus 10 may be moved upwardlyand removed from the well bore. As explained previously, means may becoupled to the lower portion of the well apparatus 10 for severing theposed on the tapered mandrel 160 by suitable fastening 75 tubularstructure 16 so that the portion of the tubular structure 16 above thestuck zone can be removed in a known manner.

FIGURES 4 and 5 show detailed views of the slip 170. FIGURE 4 showsteeth 173 and aperture 192. Shoulder 194 is disposed against the lowerportion of the head of screw 174 as may be seen in FIGURES 2B and 3B.Screws 174 and 176 and the apertures in the slips provide guides for themovement of the slips 170 and 172. As shown in the rear View of FIGUR-E5 of the slip 170, tapered section 196 is adapted for engagement withtapered mandrel 160. Slotted section 198 of slip 170 is adapted formovement along lower mandrel section 156 as shown in FIGURES 2B and 3B.Although only two slips are shown in the described embodiment of theinvention, it is to be appreciated that any number of slips havingvarious configurations can be used in practicing the invention as longas such slips engage the tubular structure so that the exible line 12can be tensioned to allow proper functioning of registration means 42.As pointed out previously, slips may be used when friction means areutilized but use of a collar locator is not precluded.

Thus, the invention provides apparatus and methods for locating stuckpoints of tubular structures in a well bore and for severing suchtubular structure without reentering the well bore. Such apparatus andmethods do not require locating collars or joints on the tubularstructure when friction means are used and the present invention is notlimited in operability to ferrous tubular structure as are many of theknown stuck point indicators.

Although a preferred embodiment of the invention has been shown anddescribed, it is to be understood that the invention is deiined by thefollowing claims. Although the claims may be presented in indentedformat to facilitate reading and understanding thereof, such formatshould not be construed as structurally or functionally limiting theclaims.

I claim:

1. A device for determining the stuck point of a tubular structuredisposed in a well bore and for severing the tubular structure, saiddevice including in combination,

5 a well apparatus coupled to a exible line and having means forengaging said tubular structure, said well apparatus including explosivemeans, said well apparatus having a locked and unlocked condition,

means coupled to the flexible line for providing upward and downwardmovement of said well apparatus in the tubular structure, registrationmeans coupled to the flexible line for recording the tension on theflexible line and for recording the depth of said well apparatus in thewell bore, lifting means coupled to the tubular structure for applyingtension thereto, and means engageable with said well apparatus forchanging said well apparatus from a locked condition to an unlockedcondition and for detonating said explosive means whereby the tubularstructure is severed. 2. The device deiined by claim 1 wherein said Wellapparatus includes release means.

3. The device defined by claim 2 wherein said release means includes amandrel member having a tapered portion.

References Cited UNITED STATES PATENTS JAMES A. LEPPINK, PrimaryExaminer.

1. A DEVICE FOR DETERMINING THE STUCK POINT OF A TUBULAR STRUCTUREDISPOSED IN A WELL BORE AND FOR SEVERING THE TUBULAR STRUCTURE, SAIDDEVICE INCLUDING IN COMBINATION, A WELL APPARATUS COUPLED TO A FLEXIBLELINE AND HAVING MEANS FOR ENGAGING SAID TUBULAR STRUCTURE, SAID WELLAPPARATUS INCLUDING EXPLOSIVE MEANS, SAID WELL APPARATUS HAVING A LOCKEDAND UNLOCKED CONDITION, MEANS COUPLED TO THE FLEXIBLE LINE FOR PROVIDINGUPWARD AND DOWNWARD MOVEMENT OF SAID WELL APPARATUS IN THE TUBULARSTRUCTURE, REGISTRATION MEANS COUPLED TO THE FLEXIBLE LINE FOR RECORDINGTHE TENSION ON THE FLEXIBLE LINE AND FOR RECORDING THE DEPTH OF SAIDWELL APPARATUS IN THE WELL BORE, LIFTING MEANS COUPLED TO THE TUBULARSTRUCTURE FOR APPLYING TENSION THERETO, AND